1. Field of Invention
The present invention generally relates to a receiver circuit, and more particularly to a receiver circuit applying a level shifter with low leakage.
2. Description of Prior Art
Semiconductor chips (dice/integrated circuits) are the most important hardware bases of modern information society. Chips with different functionalities are integrated to form an electronic system with multiple functions, and various chips with different functions exchange data and signals mutually. Signal transmitted and received by chips may have a voltage swing range between 0V and 3.3V, where 3.3V represents high state (i.e., logic 1) and 0V represents low state (i.e., logic 0), so as to construct various circuit operations. However, as semiconductor manufacturing process evolves toward advanced process of deep semi-micron, modern chips adopt low voltage devices (e.g., transistors) to build integrated circuits. In contrasts to the chips having the voltage swing range between 0V and 3.3V, the low voltage devices have a lower voltage swing range between 0V and 1.8V, such as 1.8V low voltage inverters, where 1.8V represents high state and 0V represents low state.
In order to integrate functionalities of various chips so that chips exchange data and signals mutually, each chip includes receiver circuit for receiving signals transmitted from other chip(s) and propagating signals correctly. In a conventional receiver circuit design, level shifter is applied in the receiver circuit for implementing the functionality of shifting the voltage swing range of the received signals to achieve the signal transmission between the circuit board and chips with low voltage devices. However, the conventional level shifter suffers from a current leakage path. The power consumption resulting from a leakage current flowing through the level shifter may be critically increased which leads to high power loss.